/*
 ** client.c -- a stream socket client demo
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>

#define PORT "3490" // the port client will be connecting to
#define MAXDATASIZE 100 // max number of bytes we can get at once

// get sockaddr, IPv4 or IPv6:
void *get_in_addr(struct sockaddr *sa)
{
    if (sa->sa_family == AF_INET) {
	return &(((struct sockaddr_in*)sa)->sin_addr);
    }
    return &(((struct sockaddr_in6*)sa)->sin6_addr);
}

int main(int argc, char *argv[])
{
    int sockfd, numbytes;
    char buf[MAXDATASIZE];
    struct addrinfo hints, *servinfo, *p;
    int rv;
    char s[INET6_ADDRSTRLEN];

    if (argc != 2) {
	fprintf(stderr,"usage: client hostname\n");
	exit(1);
    }

    memset(&hints, 0, sizeof hints);
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;

    if ((rv = getaddrinfo(argv[1], PORT, &hints, &servinfo)) != 0) {
	fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
	return 1;
    }

    // loop through all the results and connect to the first we can
    for(p = servinfo; p != NULL; p = p->ai_next) {
	if ((sockfd = socket(p->ai_family, p->ai_socktype,
			     p->ai_protocol)) == -1) {
	    perror("client: socket");
	    continue;
	}

	if (connect(sockfd, p->ai_addr, p->ai_addrlen) == -1) {
	    close(sockfd);
	    perror("client: connect");
	    continue;
	}

	break;

    } // for

    if (p == NULL) {
	fprintf(stderr, "client: failed to connect\n");
	return 2;
    }

    inet_ntop(p->ai_family, get_in_addr((struct sockaddr *)p->ai_addr),
	      s, sizeof s);
    printf("client: connecting to %s\n", s);
    freeaddrinfo(servinfo); // all done with this structure

    if ((numbytes = recv(sockfd, buf, MAXDATASIZE-1, 0)) == -1) {
	perror("recv");

	exit(1);
    }

    buf[numbytes] = '\0';
    printf("client: received '%s'\n",buf);

    close(sockfd);

    return 0;

} // main()
